Al-Hikmah University Journal

This study investigated the effects of mother tongue on academic performance of students in English language in Obokun local government area of Osun state, Nigeria. The study is experimental in nature. It adopts the one shot- pre-experimental research design. The population of the study consisted of all junior secondary schools.  The sample of Two hundred students were stratified into two strata, each stratum were tagged Yoruba and English class members respectively. Where the English class represent the control group, while the Yoruba class represent the treatment group. The research instrument to be used for data collection is an Achievement Test of English Language. The test-retest method was employed to establish the internal consistency of the instrument. Descriptive and inferential statistics: mean, standard deviation, Regression analysis were used. Findings from the study indicated that there is no significant difference in the performance of students in English language Achievement test based on gender both in L1 and L2 classes.  It was thus recommended that teachers should use code mix L1 and L2 when teaching difficult topics.